Zucchini, Summer (Yellow) Squash, and Tomatoes

2 Tbl. butter or margarine
2 slices onion
2 zuchinni, sliced crosswise, or roll cut(like often done in Chinese recipes)
2 Summer Squash, sliced or cut the same way as the zuchinni
1 Tbl. water
1 Tomato, cored. cut in half and cut into about 1 inch pieces
2-3 Tbl. freshly grated Parmesan cheese
2 Tbl. fresh basil, chopped

Melt butter over low heat in frying pan. Increase heat to medium and add onions, zucchini, summer squash and water. Cover and cook until squash is just crisp tender, about 3- 5 minutes, stirring with a spatula a few times. Add the tomato pieces and the parmesan cheese. Cook covered until the tomatoes are warm but not falling apart and the cheese is melted, about 1 minute. Add the fresh basil and serve warm.